The present invention relates to 1-alkoxy-polyalkyl-piperidine derivatives, a polymerizable composition comprising a) at least one ethylenically unsaturated monomer and b) a 1-alkoxy-polyalkyl-piperidine derivative. Further aspects of the present invention are a process for polymerizing ethylenically unsaturated monomers, and the use of 1-alkoxy-polyalkyl-piperidine derivatives for controlled polymerization. The intermediate N-oxyl derivatives, a composition of the N-oxyl derivatives with ethylenically unsaturated monomers and a free radical initiator X., as well as a process for polymerization are also subjects of the present invention.
The compounds of the present invention provide polymeric resin products having low polydispersity. The polymerization process proceeds with enhanced monomer to polymer conversion efficiency. In particular, this invention relates to stable free radical-mediated polymerization processes which provide homopolymers, random copolymers, block copolymers, multiblock copolymers, graft copolymers and the like, at enhanced rates of polymerization and enhanced monomer to polymer conversions.
Polymers or copolymers prepared by free radical polymerization processes inherently have broad molecular weight distributions or polydispersities which are generally higher than about four. One reason for this is that most of the free radical initiators have half lives that are relatively long, ranging from several minutes to many hours, and thus the polymeric chains are not all initiated at the same time and the initiators provide growing chains of various lengths at any time during the polymerization process. Another reason is that the propagating chains in a free radical process can react with each other in processes known as combination and disproportionation, both of which are irreversibly chain-terminating reaction processes. In doing so, chains of varying lengths are terminated at different times during the reaction process, resulting in resins consisting of polymeric chains which vary widely in length from very small to very large and which thus have broad polydispersities. If a free radical polymerization process is to be used for producing narrow molecular weight distributions, then all polymer chains must be initiated at about the same time and termination of the growing polymer-chains by combination or disproportionation processes must be avoided.
Conventional radical polymerization reaction processes pose various significant problems, such as difficulties in predicting or controlling the molecular weight, the polydispersity and the modality of the polymers produced. These prior art polymerization processes produce polymers having broad polydispersities and in some instances, low polymerization rates. Furthermore, free radical polymerization processes in bulk of the prior art are difficult to control because the polymerization reaction is strongly exothermic and an efficient heat removal in the highly viscous polymer is mostly impossible. The exothermic nature of the prior art free radical polymerization processes often severely restricts the concentration of reactants or the reactor size upon scale-up.
Due to the above mentioned uncontrollable polymerization reactions, gel formation in conventional free radical polymerization processes are also possible and cause broad molecular weight distributions and/or difficulties during filtering, drying and manipulating the product resin.
U.S. Pat. No. 4,581,429 to Solomon et al., issued Apr. 8, 1986, discloses a free radical polymerization process which controls the growth of polymer chains to produce short chain or oligomeric homopolymers and copolymers, including block and graft copolymers. The process employs an initiator having the formula (in part) Rxe2x80x2Rxe2x80x3Nxe2x80x94Oxe2x80x94X, where X is a free radical species capable of polymerizing unsaturated monomers. The reactions typically have low conversion rates. Specifically mentioned radical Rxe2x80x2Rxe2x80x3Nxe2x80x94O. groups are derived from 1,1,3,3 tetraethylisoindoline, 1,1,3,3 tetrapropylisoindoline, 2,2,6,6 tetramethylpiperidine, 2,2,5,5 tetramethylpyrrolidine or di-t-butylamine. However, the suggested compounds do not fulfill all requirements. Particularly the polymerization of acrylates does not proceed fast enough and/or the monomer to polymer conversion is not as high as desired.
Recently other attempts to develop new polymerization regulators have been published. WO 98/4408 and WO 98/30601 disclose heterocyclic compounds suitable for controlled polymerization processes. WO 98/13392 discloses open chain alkoxyamines which are derived from NO gas or from nitroso compounds.
EP-A-735 052 discloses a method for preparing thermoplastic polymers of narrow poly-dispersities by free radical-initated polymerization, which comprises adding a free radical initiator and a stable free radical agent to the monomer compound.
This method has the disadvantage that uncontrollable recombinations of initiator radicals may occur immediately after their formation, thus producing variable ratios between initiator radicals and stable free radicals. Consequently in some cases there is no good control of the polymerization process.
There is therefore still a need for polymerization processes for the preparation of narrow polydispersity polymeric resins with defined molecular weights using the economical free radical polymerization techniques. These polymerization processes will also control the physical properties of the polymers such as viscosity, hardness, gel content, processability, clarity, high gloss, durability, and the like.
The polymerization processes and resin products of the present invention are useful in many applications, including a variety of specialty applications, such as for the preparation of block copolymers which are useful as compatibilizing agents for polymer blends, or dispersing agents for coating systems or for the preparation of narrow molecular weight resins or oligomers for use in coating technologies and thermoplastic films or as toner resins and liquid immersion development ink resins or ink additives used for electrophotographic imaging processes.
Surprisingly, it has now been found that it is possible to overcome the afore mentioned shortcomings of the prior art by providing a polymerizable composition containing specific initiator compounds. Polymerization of the composition results in a polymer or copolymer of narrow polydispersity and a high monomer to polymer conversion even at relatively low temperatures and at short reaction times, making the polymerization process particularly suitable for industrial applications. The resulting copolymers are of high purity and in many cases colorless, therefore not requiring any further purification.
One object of the present invention is to provide a 1-alkoxy-polyalkyl-piperidine derivative containing a structural element of formula (I): 
wherein
G1, G2, G3, G4 are independently C1-C6alkyl with the proviso that at least one is not methyl or G1 and G2 or G3 and G4, or G1 and G2 and G3 and G4 together form a C5-C12cycloalkyl group;
G5, G6 independently are H, C1-C18alkyl, phenyl, naphthyl or a group COOC1-C18alkyl and X represents a group having at least one carbon atom and is such that the free radical X. derived from X is capable of initiating polymerization of ethylenically unsaturated monomers, with the proviso that compounds A1 and A2 are excluded: 
The alkyl radicals in the various substituents may be linear or branched. Examples of alkyl containing 1 to 18 carbon atoms are methyl, ethyl, propyl, isopropyl, butyl, 2-butyl, isobutyl, t-butyl, pentyl, 2-pentyl, hexyl, heptyl, octyl, 2-ethylhexyl, t-octyl, nonyl, decyl, undecyl, dodecyl, tridecyl, tetradecyl, hexadecyl and octadecyl.
C5-C12cycloalkyl is typically, cyclopentyl, methylcyclopentyl, dimethylcyclopentyl, cyclohexyl, methylcyclohexyl.
Preferred compounds or mixture of compounds are any of formulae A to S; 
wherein
G1, G2, G3 and G4 are independently alkyl of 1 to 4 carbon atoms, or G1 and G2 together and G3 and G4 together, or G1 and G2 together or G3 and G4 together are pentamethylene;
G5 and G6 are independently hydrogen or C1-C4 alkyl;
R, if m is 1, is hydrogen, C1-C18alkyl which is uninterrupted or C2-C18alkyl which is interrupted by one or more oxygen atoms, cyanoethyl, benzoyl, glycidyl, a monovalent radical of an aliphatic carboxylic acid having 2 to 18 carbon atoms, of a cycloaliphatic carboxylic acid having 7 to 15 carbon atoms, or an xcex1,xcex2-unsaturated carboxylic acid having 3 to 5 carbon atoms or of an aromatic carboxylic acid having 7 to 15 carbon atoms, where each carboxylic acid can be substituted in the aliphatic, cycloaliphatic or aromatic moiety by 1 to 3 xe2x80x94COOZ12 groups, in which Z12 is H, C1-C20alkyl, C3-C12alkenyl, C5-C7cycloalkyl, phenyl or benzyl; or
R is a monovalent radical of a carbamic acid or phosphorus-containing acid or a monovalent silyl radical;
R, if m is 2, is C2-C12alkenylene, C4-C12alkenylene, xylylene, a divalent radical of an aliphatic dicarboxylic acid having 2 to 36 carbon atoms, or a cycloaliphatic or aromatic dicarboxylic acid having 8-14 carbon atoms or of an aliphatic, cycloaliphatic or aromatic dicarbamic acid having 8-14 carbon atoms, where each dicarboxylic acid may be substituted in the aliphatic, cycloaliphatic or aromatic moiety by one or two xe2x80x94COOZ12 groups; or
R is a divalent radical of a phosphorus-containing acid or a divalent silyl radical;
R, if m is 3, is a trivalent radical of an aliphatic, cycloaliphatic or aromatic tricarboxylic acid, which may be substituted in the aliphatic, cycloaliphatic or aromatic moiety by xe2x80x94COOZ12, of an aromatic tricarbamic acid or of a phosphorus-containing acid, or is a trivalent silyl radical,
R, if m is 4, is a tetravalent radical of an aliphatic, cycloaliphatic or aromatic tetracarboxylic acid;
p is 1, 2 or 3,
R1 is C1-C12alkyl, C5-C7cycloalkyl, C7-C8aralkyl, C2-C18alkanoyl, C3-C5alkenoyl or benzoyl;
when p is 1,
R2 is C1-C18alkyl, C5-C7cycloalkyl, C2-C8alkenyl unsubstituted or substituted by a cyano, carbonyl or carbamide group, or is glycidyl, a group of the formula xe2x80x94CH2CH(OH)xe2x80x94Z or of the formula xe2x80x94COxe2x80x94Zxe2x80x94 or xe2x80x94CONHxe2x80x94Z wherein Z is hydrogen, methyl or phenyl; or
when p is 2,
R2 is C2-C12alkylene, C6-C12arylene, xylylene, a xe2x80x94CH2CH(OH)CH2xe2x80x94Oxe2x80x94Bxe2x80x94Oxe2x80x94CH2CH(OH)CH2xe2x80x94 group, wherein B is C2-C10alkylene, C6-C15arylene or C6-C12cycloalkylene; or, provided that R1 is not alkanoyl, alkenoyl or benzoyl, R2 can also be a divalent acyl radical of an aliphatic, cycloaliphatic or aromatic dicarboxylic acid or dicarbamic acid, or can be the group xe2x80x94COxe2x80x94; or
R1 and R2 together when p is 1 can be the cyclic acyl radical of an aliphatic or aromatic 1,2- or 1,3-dicarboxylic acid; or
R2 is a group: 
where T7 and T8 are independently hydrogen, alkyl of 1 to 18 carbon atoms, or T7 and T8 together are alkylene of 4 to 6 carbon atoms or 3-oxapentamethylene;
when p is 3,
R2 is 2,4,6-triazinyl;
when n is 1,
R3 is C2-C8-alkylene or hydroxyalkylene or C4-C22acyloxyalkylene; or
when n is 2,
R3 is (xe2x80x94CH2)2C(CH2xe2x80x94)2;
when n is 1,
R4 is hydrogen, C1-C12alkyl, C3-C5alkenyl, C7-C9aralkyl, C5-C7cycloalkyl, C2-C4hydroxyalkyl, C2-C6alkoxyalkyl, C6-C10aryl, glycidyl, a group of formula xe2x80x94(CH2)mxe2x80x94COOxe2x80x94Q or of the formula xe2x80x94(CH2)mxe2x80x94Oxe2x80x94COxe2x80x94Q wherein m is 1 or 2 and Q is C1-C4alkyl or phenyl; or
when n is 2,
R4 is C2-C12alkylene, C6-C12arylene, a group xe2x80x94CH2CH(OH)CH2xe2x80x94Oxe2x80x94Dxe2x80x94Oxe2x80x94CH2CH(OH)CH2xe2x80x94 wherein D is C2-C10alkylene, C6-C15arylene or C6-C12cycloalkylene, or a group xe2x80x94CH2CH(OZ1)CH2xe2x80x94(OCH2CH(OZ1)CH2)2xe2x80x94 wherein Z1 is hydrogen, C1-C18alkyl, allyl, benzyl, C2-C12alkanoyl or benzoyl;
R5 is hydrogen, C1-C12alkyl, allyl, benzyl, glycidyl or C2-C6alkoxyalkyl;
Q1 is xe2x80x94N(R7)xe2x80x94 or xe2x80x94Oxe2x80x94;
E is C1-C3alkylene, the group xe2x80x94CH2CH(R8)xe2x80x94Oxe2x80x94 wherein R8 is hydrogen, methyl or phenyl, the group xe2x80x94(CH2)3xe2x80x94NHxe2x80x94 or a direct bond;
R7 is C1-C18alkyl, C5-C7-cycloalkyl, C7-C12aralkyl, cyanoethyl, C6-C10-aryl, the group xe2x80x94CH2CH(R8)xe2x80x94OH; or a group of the formula: 
or a group of the formula 
wherein G is C2-C6alkylene or C6-C12arylene and R is as defined above; or
R7 is a group xe2x80x94Exe2x80x94COxe2x80x94NHxe2x80x94CH2xe2x80x94OR6;
R6 is hydrogen or C1-C18alkyl;
Formula (F) denotes a recurring structural unit of a oligomer where T is ethylene or 1,2-propylene, or is a repeating structural unit derived from an xcex1-olefin copolymer with an alkyl acrylate or methacrylate;
k is 2 to 100;
R10 is hydrogen, C1-C12alkyl or C1-C12alkoxy;
T2 has the same meaning as R4;
T3 and T4 are independently alkylene of 2 to 12 carbon atoms, or T4 is a group: 
T5 is C2-C22alkylene, C5-C7cycloalkylene, C1-C4alkylenedi(C5-C7cycloalkylene), phenylene or phenylenedi(C1-C4alkylene); 
where a, b and c are independently 2 or 3, and d is 0 or 1;
e is 3 or 4;
T7 and T8 are independently hydrogen C1-C18alkyl, or T7 and T8 together are C4-C6alkylene or 3-oxapenthamethylene;
E1 and E2, being different, each are xe2x80x94COxe2x80x94 or xe2x80x94N(E5)xe2x80x94, where E5 is hydrogen, C1-C12alkyl or C4-C22alkoxycarbonylalkyl;
E3 is hydrogen, alkyl of 1 to 30 carbon atoms, phenyl, naphthyl, said phenyl or said naphthyl substituted by chlorine or by alkyl of 1 to 4 carbon atoms, or phenylalkyl of 7 to 12 carbon atoms, or said phenylalkyl substituted by alkyl of 1 to 4 carbon atoms;
E4 is hydrogen, alkyl of 1 to 30 carbon atoms, phenyl, naphthyl or phenylalkyl of 7 to 12 carbon atoms; or
E3 and E4 together are polymethylene of 4 to 17 carbon atoms, or said polymethylene substituted by up to four alkyl groups of 1 to 4 carbon atoms; and
E6 is an aliphatic or aromatic tetravalent radical.
C3-C12alkenyl is for example propenyl, butenyl, pentenyl, hexenyl, heptenyl, octenyl, dodecenyl including their isomers.
C7-C9aralkyl is for example benzyl, phenylpropyl, xcex1,xcex1-dimethylbenzyl or xcex1-methylbenzyl.
C2-C18alkyl interrupted by at least one O atom is for example xe2x80x94CH2xe2x80x94CH2xe2x80x94Oxe2x80x94CH2xe2x80x94CH3, xe2x80x94CH2xe2x80x94CH2xe2x80x94Oxe2x80x94CH3 or xe2x80x94CH2xe2x80x94CH2xe2x80x94Oxe2x80x94CH2xe2x80x94CH2xe2x80x94CH2xe2x80x94Oxe2x80x94CH2xe2x80x94CH3. It is preferably derived from polyethlene glycol. A general description is xe2x80x94((CH2)axe2x80x94O)bxe2x80x94H/CH3, wherein a is a number from 1 to 6 and b is a number from 2 to 10.
If R is a monovalent radical of a carboxylic acid, it is, for example, an acetyl, caproyl, stearoyl, acryloyl, methacryloyl, benzoyl or xcex2-(3,5-di-tert-butyl-4-hydroxyphenyl)propionyl radical.
If R is a monovalent silyl radical, it is, for example, a radical of the formula xe2x80x94(CjH2j)xe2x80x94Si(Zxe2x80x2)2Zxe2x80x3, in which j is an integer in the range from 2 to 5, and Zxe2x80x2 and Zxe2x80x3, independently of one another, are C1-C4alkyl or C1-C4alkoxy.
If R is a divalent radical of a dicarboxylic acid, it is, for example, a malonyl, succinyl, glutaryl, adipoyl, suberoyl, sebacoyl, maleoyl, itaconyl, phthaloyl, dibutylmalonyl, dibenzylmalonyl, butyl(3,5-di-tert-butyl-4-hydroxybenzyl)malonyl or bicycloheptenedicarbonyl radical or a group of the formula: 
If R is a trivalent radical of a tricarboxylic acid, it is, for example, a trimellitoyl, citryl or nitrilotriacetyl radical.
If R is a tetravalent radical of a tetracarboxylic acid, it is, for example, the tetravalent radical of butane-1,2,3,4-tetracarboxylic acid or of pyromellitic acid.
If R is a divalent radical of a dicarbamic acid, it is, for example, hexamethylenedicarbamoyl or 2,4-toluylenedicarbamoyl radical.
C1-C18alkanoyl is for example, formyl, propionyl, butyryl, octanoyl, dodecanoyl but preferably acetyl and C3-C5alkenoyl is in particular acryloyl.
Any C2-C12alkylene radicals are, for example, ethylene, propylene, 2,2-dimethylpropylene, tetramethylene, hexamethylene, octamethylene, decamethylene or dodecamethylene.
Any C6-C15arylene substituents are, for example, o-, m- or p-phenylene, 1,4-naphthylene or 4,4xe2x80x2-diphenylene.
C6-C12cycloalkylene is, in particular, cyclohexylene.
Hydroxyl-, cyano-, alkoxycarbonyl- or carbamide-substituted C1-C4alkyl can be, for example, 2-hydroxyethyl, 2-hydroxypropyl, 2-cyanoethyl, methoxycarbonylmethyl, 2-ethoxycarbonylethyl, 2-aminocarbonylpropyl or 2-(dimethylaminocarbonyl)ethyl.
Any C2-C6alkoxyalkyl substituents are, for example, methoxymethyl, ethoxymethyl, propoxymethyl, tert-butoxymethyl, ethoxyethyl, ethoxypropyl, n-butoxyethyl, tert-butoxyethyl, isopropoxyethyl or propoxypropyl.
Preferably G6 is hydrogen and G5 is hydrogen or C1-C4alkyl.
Preferably G1, G2, G3 and G4 are independently C1-C4alkyl, with the proviso that at least one is different from methyl.
More preferred G1 and G3 are methyl and G2 and G4 are ethyl or propyl.
In another preferred group of compounds G1 and G2 are methyl and G3 and G4 are ethyl or propyl.
Preferably X is selected from the group consisting of xe2x80x94CH2-aryl, 
(C5-C6cycloalkyl)2CCN, (C1-C12alkyl)2CCN, xe2x80x94CH2CHxe2x95x90CH2, (C1-C12)alkyl-CR20xe2x80x94C(O)xe2x80x94(C1-C12)alkyl, (C1-C12)alkyl-CR20xe2x80x94C(O)xe2x80x94(C6-C10)aryl, (C1-C12)alkyl-CR20xe2x80x94C(O)xe2x80x94(C1-C12)alkoxy, (C1-C12)alkyl-CR20xe2x80x94C(O)-phenoxy, (C1-C12)alkyl-CR20xe2x80x94C(O)xe2x80x94N-di(C1-C12)alkyl, (C1-C12)alkyl-CR20xe2x80x94COxe2x80x94NH(C1xe2x80x94C12)alkyl, (C1-C12)alkyl-CR20xe2x80x94COxe2x80x94NH2, xe2x80x94CH2CHxe2x95x90CHxe2x80x94CH3, xe2x80x94CH2xe2x80x94C(CH3)xe2x95x90CH2, xe2x80x94CH2xe2x80x94CHxe2x95x90CH-phenyl, 
wherein
R20 is hydrogen or C1-C12alkyl;
the aryl groups are phenyl or naphthyl which are unsubstituted or substituted with C1-C12alkyl, halogen, C1-C12alkoxy, C1-C12alkylcarbonyl, glycidyloxy, OH, xe2x80x94COOH or xe2x80x94COOC1-C12alkyl.
More preferred are compounds, wherein X is selected from the group consisting of xe2x80x94CH2-phenyl, CH3CH-phenyl, (CH3)2C-phenyl, (C5-C6cycloalkyl)2CCN, (CH3)2CCN, xe2x80x94CH2CHxe2x95x90CH2, CH3CHxe2x80x94CHxe2x95x90CH2(C1-C8alkyl)CR20xe2x80x94C(O)-phenyl, (C1-C8)alkyl-CR20xe2x80x94C(O)xe2x80x94(C1-C8)alkoxy, (C1-C8)alkyl-CR20xe2x80x94C(O)xe2x80x94(C1-C8)alkyl, (C1-C8)alkyl-CR20xe2x80x94C(O)xe2x80x94N-di(C1-C8)alkyl, (C1-C8) alkyl-CR20xe2x80x94C(O)xe2x80x94NH(C1-C8)alkyl, (C1-C8)alkyl-CR20xe2x80x94C(O)xe2x80x94NH2, wherein R20 is hydrogen or (C1-C8)alkyl.
Particularly preferred are compounds, wherein X is selected from the group consisting of xe2x80x94CH2-phenyl, CH3CH-phenyl, (CH3)2C-phenyl, (C5-C6cycloalkyl)2CCN, (CH3)2CCN, xe2x80x94CH2CHxe2x95x90CH2, CH3CHxe2x80x94CHxe2x95x90CH2 (C1-C4alkyl)CR20xe2x80x94C(O)-phenyl, (C1-C4)alkyl-CR20xe2x80x94C(O)xe2x80x94(C1-C4)alkoxy, (C1-C4)alkyl-CR20xe2x80x94C(O)xe2x80x94(C1-C4)alkyl, (C1-C4)alkyl-CR20xe2x80x94C(O)xe2x80x94N-di(C1-C4)alkyl, (C1-C4)alkyl-CR20xe2x80x94C(O)xe2x80x94NH(C1-C4)alkyl, (C1-C4)alkyl-CR20xe2x80x94C(O)xe2x80x94NH2, wherein R20 is hydrogen or (C1-C4)alkyl.
In a preferred group of compounds X contains no open chain alkylether group.
Preferred compounds are those of formula A, B, O or P, particularly preferred of formula A, B or O and more preferred of formula A or B, wherein the substituents have the meanings as defined before.
A preferred group of compounds are those of formula A, B or O, wherein
m is 1,
R is hydrogen, C1-C18alkyl which is uninterrupted or interrupted by one or more oxygen atoms, cyanoethyl, benzoyl, glycidyl, a monovalent radical of an aliphatic carboxylic acid having 2 to 18 carbon atoms, of a cycloaliphatic carboxylic acid having 7 to 15 carbon atoms, or an xcex1,xcex2-unsaturated carboxylic acid having 3 to 5 carbon atoms or of an aromatic carboxylic acid having 7 to 15 carbon atoms;
p is 1;
R1 is C1-C12alkyl, C5-C7cycloalkyl, C7-C8aralkyl, C2-C18alkanoyl, C3-C5alkenoyl or benzoyl;
R2 is C1-C18alkyl, C5-C7cycloalkyl, C2-C8alkenyl unsubstituted or substituted by a cyano, carbonyl or carbamide group, or is glycidyl, a group of the formula xe2x80x94CH2CH(OH)xe2x80x94Z or of the formula xe2x80x94COxe2x80x94Z or xe2x80x94CONHxe2x80x94Z wherein Z is hydrogen, methyl or phenyl.
Amongst the group of compounds of formula A, B or O those are more preferred, wherein
R is hydrogen, C1-C18alkyl, cyanoethyl, benzoyl, glycidyl, a monovalent radical of an aliphatic, carboxylic acid;
R1 is C1-C12alkyl, C7-C8aralkyl, C2-C18alkanoyl, C3-C5alkenoyl or benzoyl;
R2 is C1-C18alkyl, glycidyl, a group of the formula xe2x80x94CH2CH(OH)xe2x80x94Z or of the formula xe2x80x94COxe2x80x94Z, wherein Z is hydrogen, methyl or phenyl.
A further preference for this subgroup is that G6 is hydrogen and G5 is hydrogen or C1-C4alkyl, G1 and G3 are methyl and G2 and G4 are ethyl or propyl or G1 and G2 are methyl and G3 and G4 are ethyl or propyl.
In addition for the compounds of formula A, B or O a preferred group X is selected from the group consisting of xe2x80x94CH2-phenyl, CH3CH-phenyl, (CH3)2C-phenyl, (C5-C6cycloalkyl)2CCN, (CH3)2CCN, xe2x80x94CH2CHxe2x95x90CH2, CH3CHxe2x80x94CHxe2x95x90CH2, (C1-C4alkyl)CR20xe2x80x94C(O)-phenyl, (C1-C4)alkyl-CR20xe2x80x94C(O)xe2x80x94(C1-C4)alkoxy, (C1-C4)alkyl-CR20xe2x80x94C(O)xe2x80x94(C1-C4)alkyl, (C1-C4)alkyl-CR20xe2x80x94C(O)xe2x80x94N-di(C1-C4)alkyl, (C1-C4)alkyl-CR20xe2x80x94C(O)xe2x80x94NH(C1-C4)alkyl, (C1-C4)alkyl-CR20xe2x80x94C(O)xe2x80x94NH2, wherein R20 is hydrogen or (C1-C4)alkyl.
Most preferred are the compounds of formula (A), wherein G5 and G6 are hydrogen or methyl, G1 and G3 are methyl and G2 and G4 are ethyl or G1 and G2 are methyl and G3 and G4 are ethyl;
m is 1; R is hydrogen, C1-C18alkyl or a group xe2x80x94C(O)xe2x80x94(C2-C18)alkyl; and
X is xe2x80x94CH2-phenyl, CH3CH-phenyl, (CH3)2C-phenyl, (C5-C6cycloalkyl)2CCN, (CH3)2CCN, xe2x80x94CH2CHxe2x95x90CH2, CH3CHxe2x80x94CHxe2x95x90CH2 (C1-C4alkyl)CR20xe2x80x94C(O)-phenyl, (C1-C4)alkyl-CR20xe2x80x94C(O)xe2x80x94(C1-C4)alkoxy, (C1-C4)alkyl-CR20xe2x80x94C(O)xe2x80x94(C1-C4)alkyl, (C1-C4)alkyl-CR20xe2x80x94C(O)xe2x80x94N-di(C1-C4)alkyl, (C1-C4)alkyl-CR20xe2x80x94C(O)xe2x80x94NH(C1-C4)alkyl, (C1-C4)alkyl-CR20xe2x80x94C(O)xe2x80x94NH2, wherein R20 is hydrogen or (C1-C4)alkyl.
If R is C1-C18alkyl, propyl is particularly preferred.
If R is xe2x80x94C(O)xe2x80x94(C2-C18)alkyl, xe2x80x94C(O)xe2x80x94C11H23 and xe2x80x94C(O)xe2x80x94C17H35 are particularly preferred.
A further subject of the invention is a polymerizable composition, comprising
a) at least one ethylenically unsaturated monomer or oligomer, and
b) a 1-alkoxy-polyalkyl-piperidine derivative containing a structural element of formula (I): 
wherein
G1, G2, G3, G4 are independently C1-C6alkyl with the proviso that at least one is not methyl or G1 and G2 or G3 and G4, or G1 and G2 and G3 and G4 together form a C5-C12cycloalkyl group;
G5, G6 independently are H, C1-C18alkyl, phenyl, naphthyl or a group COOC1-C18alkyl and X represents a group having at least one carbon atom and is such that the free radical X. derived from X is capable of initiating polymerization of ethylenically unsaturated monomers, with the proviso that compounds A1 and A2 are excluded: 
Definitions for the substituents and preferred formulas have already been given. They apply also for the composition including the preferences.
Typically the ethylenically unsaturated monomer or oligomer is selected from the group consisting of ethylene, propylene, n-butylene, i-butylene, styrene, substituted styrene, conjugated dienes, acrolein, vinyl acetate, vinylpyrrolidone, vinylimidazole, maleic anhydride, (alkyl)acrylic acidanhydrides, (alkyl)acrylic acid salts, (alkyl)acrylic esters, (meth)acrylo-nitriles, (alkyl)acrylamides, vinyl halides or vinylidene halides.
Preferred ethylenically unsaturated monomers are ethylene, propylene, n-butylene, i-butylene, isoprene, 1,3-butadiene, xcex1-C5-C18alkene, styrene, xcex1-methyl styrene, p-methyl styrene or a compound of formula CH2xe2x95x90C(Ra)xe2x80x94(Cxe2x95x90Z)xe2x80x94Rb, wherein Ra is hydrogen or C1-C4alkyl, Rb is NH2, O31 (Me+), glycidyl, unsubstituted C1-C18alkoxy, C2-C100alkoxy interrupted by at least one N and/or O atom, or hydroxy-substituted C1-C18alkoxy, unsubstituted C1-C18alkylamino, di(C1-C18alkyl)amino, hydroxy-substituted C1-C18alkylamino or hydroxy-substituted di(C1-C18alkyl)amino, xe2x80x94Oxe2x80x94CH2xe2x80x94CH2xe2x80x94N(CH3)2 or xe2x80x94Oxe2x80x94CH2xe2x80x94CH2xe2x80x94N+H (CH3)2 Anxe2x88x92;
Anxe2x88x92 is a anion of a monovalent organic or inorganic acid;
Me is a monovalent metal atom or the ammonium ion.
Z is oxygen or sulfur.
Examples for Ra as C2-C100alkoxy interrupted by at least one O atom are of formula: 
wherein Rc is C1-C25alkyl, phenyl or phenyl substituted by C1-C18alkyl, Rd is hydrogen or methyl and v is a number from 1 to 50. These monomers are for example derived from non ionic surfactants by acrylation of the corresponding alkoxylated alcohols or phenols. The repeating units may be derived from ethylene oxide, propylene oxide or mixtures of both.
Further examples of suitable acrylate or methacrylate monomers are given below. 
Anxe2x88x92, wherein Anxe2x88x92 and Ra have the meaning as defined above and Re is methyl or benzyl. Anxe2x88x92 is preferably Clxe2x88x92, Brxe2x88x92 or xe2x88x92O3Sxe2x80x94CH3.
Further acrylate monomers are 
Examples for suitable monomers other than acrylates are 
Preferably Ra is hydrogen or methyl, Rb is NH2, gycidyl, unsubstituted or with hydroxy substituted C1-C4alkoxy, unsubstituted C1-C4alkylamino, di(C1-C4alkyl)amino, hydroxy-substituted C1-C4alkylamino or hydroxy-substituted di(C1-C4alkyl)amino; and Z is oxygen.
Particularly preferred ethylenically unsaturated monomers are styrene, methylacrylate, ethylacrylate, butylacrylate, isobutylacrylate, tert. butylacrylate, hydroxyethylacrylate, hydroxypropylacrylate, dimethylaminoethylacrylate, glycidylacrylates, methyl(meth)acrylate, ethyl(meth)acrylate, butyl(meth)acrylate, hydroxyethyl(meth)acrylate, hydroxypropyl(meth)acrylate, dimethylaminoethyl(meth)acrylate, glycidyl(meth)acrylates, acrylonitrile, acrylamide, methacrylamide or dimethylaminopropyl-methacrylamide.
Preferably the initiator compound is present in an amount of from 0.01 mol-% to 30 mol-%, more preferably in an amount of from 0.1 mol-% to 20 mol-% and most preferred in an amount of from 0.5 mol-% to 10 mol-% based on the monomer or monomer mixture.
When monomer mixtures are used mol % is calculated on the average molecular weight of the mixture.
Another subject of the present invention is a process for preparing an oligomer, a cooligomer, a polymer or a copolymer (block or random) by free radical polymerization of at least one ethylenically unsaturated monomer or oligomer, which comprises (co)polymerizing the monomer or monomers/oligomers in the presence of an initiator compound containing a structural element of formula (I) under reaction conditions capable of effecting scission of the Oxe2x80x94C bond to form two free radicals, the radical .X being capable of initiating polymerization.
Preferably scission of the Oxe2x80x94C bond is effected by ultrasonic treatment, heating or exposure to electromagnetic radiation, ranging from xcex3 to microwaves.
More preferably the scission of the Oxe2x80x94C bond is effected by heating and takes place at a temperature of between 50xc2x0 C. and 160xc2x0 C.
The process may be carried out in the presence of an organic solvent or in the presence of water or in mixtures of organic solvents and water. Additional cosolvents or surfactants, such as glycols or ammonium salts of fatty acids, may be present. Other suitable cosolvents are described hereinafter.
Preferred processes use as little solvents as possible. In the reaction mixture it is preferred to use more than 30% by weight of monomer and initiator, particularly preferably more than 50% and most preferrably more than 80%.
If organic solvents are used, suitable solvents or mixtures of solvents are typically pure alkanes (hexane, heptane, octane, isooctane), hydrocarbons (benzene, toluene, xylene), halogenated hydrocarbons (chlorobenzene), alkanols (methanol, ethanol, ethylene glycol, ethylene glycol monomethyl ether), esters (ethyl acetate, propyl, butyl or hexyl acetate) and ethers (diethyl ether, dibutyl ether, ethylene glycol dimethyl ether), or mixtures thereof.
The aqueous polymerization reactions can be supplemented with a water-miscible or hydrophilic cosolvent to help ensure that the reaction mixture remains a homogeneous single phase throughout the monomer conversion. Any water-soluble or water-miscible cosolvent may be used, as long as the aqueous solvent medium is effective in providing a solvent system which prevents precipitation or phase separation of the reactants or polymer products until after all polymerization reactions have been completed. Exemplary cosolvents useful in the present invention may be selected from the group consisting of aliphatic alcohols, glycols, ethers, glycol ethers, pyrrolidines, N-alkyl pyrrolidinones, N-alkyl pyrrolidones, polyethylene glycols, polypropylene glycols, amides, carboxylic acids and salts thereof, esters, organosulfides, sulfoxides, sulfones, alcohol derivatives, hydroxyether derivatives such as butyl carbitol or cellosolve, amino alcohols, ketones, and the like, as well as derivatives thereof and mixtures thereof. Specific examples include methanol, ethanol, propanol, dioxane, ethylene glycol, propylene glycol, diethylene glycol, glycerol, dipropylene glycol, tetrahydrofuran, and other water-soluble or water-miscible materials, and mixtures thereof. When mixtures of water and water-soluble or water-miscible organic liquids are selected as the aqueous reaction media, the water to cosolvent weight ratio is typically in the range of about 100:0 to about 10:90.
The process is particularly useful for the preparation of block copolymers. Block copolymers are, for example, block copolymers of polystyrene and polyacrylate (e.g., poly(styrene-co-acrylate) or poly(styrene-co-acrylate-co-styrene). They are usefull as adhesives or as compatibilizers for polymer blends or as polymer toughening agents. Poly(methylmethacrylate-co-acrylate) diblock copolymers or poly(methylacrylate-co-acrylate-co-methacrylate) triblock copolymers) are useful as dispersing agents for coating systeme, as coating additives (e.g. rheological agents, compatibilizers, reactive diluents) or as resin component in coatings(e.g. high solid paints) Block copolymers of styrene, (meth)acrylates and/or acrylonitrile are useful for plastics, elastomers and adhesives.
Furthermore, block copolymers of this invention, wherein the blocks alternate between polar monomers and non-polar monomers, are useful in many applications as amphiphilic surfactants or dispersants for preparing highly uniform polymer blends. The (co)polymers of the present invention may have a number average molecular weight from 1000 to 400000 g/mol, preferably from 2000 to 250000 g/mol and, more preferably, from 2000 to 200000 g/mol. When produced in bulk, the number average molecular weight may be up to 500000 (with the same minimum weights as mentioned above). The number average molecular weight may be determined by size exclusion chromatography (SEC), gel permeation chromatography (GPC), matrix assisted laser desorption/ionization mass spectrometry (MALDI-MS) or, if the initiator carries a group which can be easily distinguished from the monomer(s), by NMR spectroscopy or other conventional methods.
The polymers or copolymers of the present invention have preferably a polydispersity of from 1.0 to 2, more preferably of from 1.1 to 1.9 and most preferably from 1.2 to 1.8.
Thus, the present invention also encompasses in the synthesis novel block, multi-block, star, gradient, random, hyperbranched and dendritic copolymers, as well as graft or copolymers.
The polymers prepared by the present invention are useful for following applications:
adhesives, detergents, dispersants, emulsifiers, surfactants, defoamers, adhesion promoters, corrosion inhibitors, viscosity improvers, lubricants, rheology modifiers, thickeners, crosslinkers, paper treatment, water treatment, electronic materials, paints, coatings, photography, ink materials, imaging materials, superabsorbants, cosmetics, hair products, preservatives, biocide materials or modifiers for asphalt, leather, textiles, ceramics and wood.
Because the present polymerizaton is a xe2x80x9clivingxe2x80x9d polymerization, it can be started and stopped practically at will. Furthermore, the polymer product retains the functional alkoxyamine group allowing a continuation of the polymerization in a living matter. Thus, in one embodiment of this invention, once the first monomer is consumed in the initial polymerizing step a second monomer can then be added to form a second block on the growing polymer chain in a second polymerization step. Therefore it is possible to carry out additional polymerizations with the same or different monomer(s) to prepare multi-block copolymers. Furthermore, since this is a radical polymerization, blocks can be prepared in essentially any order. One is not necessarily restricted to preparing block copolymers where the sequential polymerizing steps must flow from the least stabilized polymer intermediate to the most stabilized polymer intermediate, such as is the case in ionic polymerization. Thus it is possible to prepare a multi-block copolymer in which a polyacrylonitrile or a poly(meth)-acrylate block is prepared first, then a styrene or butadiene block is attached thereto, and so on.
Furthermore, there is no linking group required for joining the different blocks of the present block copolymer. One can simply add successive monomers to form successive blocks.
A plurality of specifically designed polymers and copolymers are accessible by the present invention, such as star and graft (co)polymers as described, inter alia, by C. J. Hawker in Angew. Chemie, 1995, 107, pages 1623-1627, dendrimers as described by K. Matyaszewski et al. in Macrmolecules 1996, Vol 29, No. 12, pages 4167-4171, graft (co)polymers as described by C. J. Hawker et al. in Macromol. Chem. Phys. 198, 155-166(1997), random copolymers as described by C. J. Hawker in Macromolecules 1996, 29, 2686-2688, or diblock and triblock copolymers as described by N. A. Listigovers in Macromolecules 1996, 29, 8992-8993.
A further subject of the present invention is a polymer or oligomer, having attached at least one initiator group xe2x80x94X and at least one oxyamine group of formula (Ia): 
wherein G1, G2, G3, G4, G5 and G6 are as defined above, obtainable by the above described process.
The compounds of formula (I) may be prepared from the corresponding nitroxides, which are therefore intermediates for the compounds of formula (I).
Therefore still another subject of the present invention is a 1-oxy-polyalkyl-piperidine derivative containing a structural element of formula (II): 
wherein
G1, G2, G3, G4 are independently C1-C6alkyl with the proviso that at least one is not methyl or G1 and G2 or G3 and G4, or G1 and G2 and G3 and G4 together form a C5-C12 cycloalkyl group;
G5, G6 independently are H, C1-C18alkyl, phenyl, naphthyl or a group COOC1-C18alkyl, with the proviso that compounds B1, B2 and B3 are excluded: 
Definitions for the substituents as well as their preferences have already been given. They apply also for the compounds of formula (II). In particular the corresponding formulas (A) to (S) and their preferred meanings are also preferred for the respective N-oxyls.
Also subject of the present invention is a polymerizable composition, comprising
a) at least one ethylenically unsaturated monomer or oligomer, and
b) a compound of formula (II) and c) a radical iniator X. capable of initiating polymerization of ethylenically unsaturated monomers.
The production of C-centered radicals X. is described, inter alia, in Houben Weyl, Methoden der Organischen Chemie, Vol. E 19a, pages 60-147. These methods can be applied in general analogy.
The source of radicals X. may be a bis-azo compound, a peroxide or a hydroperoxide.
Preferably, the source of radicals X. is 2,2xe2x80x2-azobisisobutyronitrile, 2,2xe2x80x2-axobis(2-methyl-butyronitrile), 2,2xe2x80x2-azobis(2,4-dimethylvaleronitrile), 2,2xe2x80x2-azobis(4-methoxy-2,4-dimethylvaleronitrile), 1,1xe2x80x2-azobis(1-cyclohexanecarbonitrile), 2,2xe2x80x2-azobis(isobutyramide) dihydrate, 2-phenylazo-2,4-dimethyl-4-methoxyvaleronitrile, dimethyl-2,2xe2x80x2-azobisisobutyrate, 2-(carbamoylazo)isobutyronitrile, 2,2xe2x80x2-azobis(2,4,4-trimethylpentane), 2,2xe2x80x2-azobis(2-methylpropane), 2,2xe2x80x2-azobis(N,Nxe2x80x2-dimethyleneisobutyramidine), free base or hydrochloride, 2,2xe2x80x2-azobis(2-amidinopropane), free base or hydrochloride, 2,2xe2x80x2-azobis{2-methyl-N-[1,1-bis (hydroxymethyl)ethyl]propionamide} or 2,2xe2x80x2-azobis{2-methyl-N-[1,1-bis(hydroxymethyl)-2-hydrozyethyl]propionamide.
Preferred peroxides and hydroperoxides are acetyl cyclohexane sulphonyl peroxide, diisopropyl peroxy dicarbonate, t-amyl perneodecanoate, t-butyl perneodecanoate, t-butyl perpivalate, t-amylperpivalate, bis(2,4-dichlorobenzoyl)peroxide, diisononanoyl peroxide, didecanoyl peroxide, dioctanoyl peroxide, dilauroyl peroxide, bis (2-methylbenzoyl) peroxide, disuccinic acid peroxide, diacetyl peroxide, dibenzoyl peroxide, t-butyl per 2-ethylhexanoate, bis-(4-chlorobenzoyl)-peroxide, t-butyl perisobutyrate, t-butyl permaleinate, 1,1-bis(t-butylperoxy) 3,5,5-trimethylcyclohexane, 1,1-bis(t-butylperoxy)cyclohexane, t-butyl peroxy isopropyl carbonate, t-butyl perisononaoate, 2,5-dimethylhexane 2,5-dibenzoate, t-butyl peracetate, t-amyl perbenzoate, t-butyl perbenzoate, 2,2-bis (t-butylperoxy) butane, 2,2bis (t-butylperoxy) propane, dicumyl peroxide, 2,5-dimethylhexane-2,5-di-t-butylperoxide, 3-t-butylperoxy 3-phenylphthalide, di-t-amyl peroxide, xcex1, xcex1xe2x80x2-bis(t-butylperoxy isopropyl) benzene, 3,5-bis (t-butylperoxy)3,5-dimethyl 1,2-dioxolane, di-t-butyl peroxide, 2,5-dimethylhexyne-2,5di-t-butylperoxide, 3,3,6,6,9,9-hexamethyl 1,2,4,5-tetraoxa cyclononane, p-menthane hydroperoxide, pinane hydroperoxide, diisopropylbenzene mono-xcex1-hydroperoxide, cumene hydroperoxide or t-butyl hydroperoxide.
These compounds are commercially available.
If more than one radical source is used, a mixture of substitution patterns is obtainable.
The radical source is preferably present in an amount of from 0.01 mol-% to 30 mol-%, more preferred in an amount of from 0.1 mol-% to 20 mol-% and most preferred in an amount of from 0.5 mol-% to 10 mol-% based on the monomer or monomer mixture.
The molar ratio of the radical source to the compound of formulae II may be from 1:10 to 10:1, preferably from 1:5 to 5:1 and more preferably from 1:2 to 2:1.
Still another subject of the present invention is a process for preparing an oligomer, a cooligomer, a polymer or a copolymer (block or random) by free radical polymerization of at least one ethylenically unsaturated monomer/oligomer, which comprises subjecting the above composition to heat or actinic radiation.
Definitions and preferences for the various substituents have already been mentioned with respect to the initiator compounds. They apply also for the other subjects of the invention including the preferences.
The initiators containing a structural element of formula I may be prepared by known methods.
DE 26 21 841, U.S. Pat. No. 4,131,599 and DE 26 30 798 for example describe the preparation of 2,6-diethyl-2,3,6-trimethyl-4-oxopiperidine and 2,6-dipropyl-3-ethyl-2,6-dimethyl-4-oxo-piperidine, which are intermediates for the corresponding 1-oxo compounds.
Another method for the preparation of 2,2-dimethyl-6,6-dialkyl-4-oxopiperidine is described by F. Asinger, M. Thiel, H. Baltz, Monatshefte fxc3xcr Chemie 88, 464 (1957) or by J. Bobbittt et al. in J. Org. Chem. 58, 4837 (1993).
The oxidation of the piperidine compound to 1-oxo-piperidine derivatives is well known in the art and for example described by L. B. Volodarsky, V. A. Reznikov, V. I. Ovcharenko in Synthetic Chemistry of Stable Nitroxides, CRC Press, Boca Raton 1994.
The nitroxides are then transformed into the NOR compounds of formula (I) or formulae (A) to (S) respectively, according to standard methods. Examples for suitable reactions are described in T. J. Connolly, M. V. Baldovi, N. Mohtat, J. C. Scaiano.: Tet. Lett. 37, 4919 (1996), I. Li, B. A. Howell et al.: Polym. Prepr. 36, 469 (1996), K. Matyjaszewski.: Macromol. Symp. 111, 47-61 (1996), P. Stipa, L. Greci, P. Carloni, E. Damiani.: Polym. Deg. Stab. 55, 323 (1997), Said Oulad Hammouch, J. M. Catala.: Macromol. Rapid Commun. 17, 149-154 (1996), Walchuk et al.: Polymer Preprints 39, 296 (1998) or Tan Ren, You-Cheng Liu, Qing-Xiang Guo.: Bull. Chem. Soc. Jpn. 69, 2935 (1996).
The compounds containing a structural element of formula (I) are useful compounds for the preparation of oligomers, cooligomers, polymers or copolymers. Hence a further subject of the invention is there use as initiators for the polymerization of ethylenically unsaturated monomers.
The following examples illustrate the invention.
A) Preparation of Compounds
2,6-diethyl-2,3,6-trimethyl-4-oxopiperidine and 2,6-dipropyl-3-ethyl-2,6-dimethyl-4-oxo-piperidine are prepared according to example 1 and 2 of DE 26 21 841.